1. field of the Invention
Record manufacturing equipment
2. Description of the Prior Art
All records are now manufactured by automatic machinery. Usually a record-making machine includes a lower record press platen and an upper record press platen. Mechanical means are provided for moving the record press platens towards each other. Attached to each record press platen is a record mold. Conduits extend through each record mold through which steam and a cooling liquid (e.g. water) are alternately passed.
A center hold down ring is provided for securing a record stamper to each record mold. Each record stamper stamps grooves on a side of the record. Usually each record stamper is provided with a conical edge and outwardly of said conical edge said record stamper slopes towards the record press platen with which it moves.
In molding a record, a plastic charge is placed between the upper record press platen and the lower record press platen when the respective record press platens are spaced apart from each other. The record press platens are brought immediately adjacent each other. Steam is directed through each record mold to increase the flow of the plastic. The movement of the stampers towards each other causes the plastic to fill the grooves of the respective stampers and flow outwardly. A cooling liquid is passed through the respective record molds to assist in cooling the plastic. Usually the plastic flashes beyond the edge of the stampers since it continues to flow radially outwardly as the stamping continues. This is undesirable in that the flash constitutes wasted material which is usually recycled.
It is extremely desirable for the time cycle for stamping a record be as low as possible for economic reasons. Still further, with many of the prior art record-pressing machines, there was a tendency for voids to be formed in the grooves not providing the desired fidelity. This, of course, was undesirable.
It is clear that if a record press machine could be devised which could minimize flash, have a low cycling time and minimize the amount of voids formed while providing better grooves that such a machine would find widespread use.